SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ed9bf8fb21796baf9f74665ba25a6d2a022162f7710be69915a017cf7294b3c' 
  AND token = 'Z38vPtJnArR+v3WBdndeUkQvZhd/6VQtJBW+Cr0GY+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}